The present invention relates to a fuel container with a molded component for the fuel container having excellent gasoline barrier properties, thermal fusion properties, and mechanical strength mounted on a fuel container body.
In recent years, in the field of fuel containers typically used in automobiles, fuel containers made of a thermoplastic resin have increasingly replaced fuel containers made of metal, because of their reduced weight, good rust prevention properties, ease of molding and processing and recycle properties.
However, a fuel container made of a thermoplastic resin causes the problem of permeation and volatilization of the gasoline component from the fuel container body. To cope with this problem, a multilayered fuel container comprising ethylene-vinyl alcohol copolymer (hereinafter, referred to as EVOH), which has high gas barrier properties, has been developed (e.g., Japanese Laid-Open Patent Publication No. 9-29904). Thus, EVOH contained in a fuel container significantly contributes to solving the problem of permeation and volatilization of the gasoline component from the fuel container body.
On the other hand, molded components provided in the fuel container (for example, a fuel tube, a vent line of a fuel filler port, a pressure relief valve and connectors connecting these elements to the container body) generally are made of high density polyethylene. For this reason, permeation and volatilization of the fuel occur. Therefore, even if the fuel container body has good gas barrier properties, fuel may permeate and volatilize from the molded components connected thereto, in an amount that cannot be ignored.
Therefore, it seems advantageous to use a barrier resin (e.g., EVOH) in place of high density polyethylene. When only the barrier resin is used for the molded component for a fuel container, the problem of permeation and volatilization of gasoline can be solved, but the thermal fusion properties to the fuel container body, the mechanical strength, and the impact resistance are unsatisfactory.
In this context, a molded component for a fuel container that can provide excellent performance in gasoline barrier properties, thermal fusion properties and mechanical strength is desired. Fuel containers provided with such a molded component improve with regard to the leakage of fuel from the molded component significantly.
The present invention relates to a fuel container comprising a fuel container body and a molded component mounted on the fuel container, the molded component comprising a barrier resin (A) having a solubility parameter (calculated from the Fedors"" equation) of more than 11 and a thermoplastic resin (B) having a solubility parameter (calculated from the Fedors"" equation) of not more than 11, the barrier resin (A) and the thermoplastic resin (B) being mixed or laminated.
In a preferable embodiment, the molded component is a single layered molded component that is molded from a blended resin composition 5 to 70% by weight (hereinafter referred to as wt %) of the barrier resin (A) and 30 to 95 wt % of the thermoplastic resin (B).
In a preferable embodiment, a gasoline permeation amount of the barrier resin (A) is not more than 100 gxc2x720 xcexcm/m2xc2x7day (measured at 40xc2x0 C.-65% RH).
In a preferable embodiment, the barrier resin (A) is at least one selected from the group consisting of polyvinyl alcohol resin, polyamide and aliphatic polyketone.
In a preferable embodiment, the barrier resin (A) is an ethylene-vinyl alcohol copolymer having an ethylene content of 5 to 60% by mol (hereinafter referred to as mol %) and a degree of saponification of at least 85%.
In another preferable embodiment, the thermoplastic resin (B) is a polyolefin resin.
In a preferable embodiment, the polyolefin resin is selected from the group consisting of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol % and a degree of saponification of at least 40%, carboxylic acid-modified polyolefin and boronic acid-modified polyolefin.
In another preferable embodiment, the thermoplastic resin (B) comprises a compatibilizer (C) and a thermoplastic resin (D) having a solubility parameter (calculated from the Fedors"" equation) of not more than 11 other than the compatibilizer (C), and a blending ratio of components, (A), (C) and (D) is 5 to 70 wt % for (A), 1 to 85 wt % for (C), and 10 to 94 wt % for (D).
In a more preferable embodiment, the compatibilizer (C) is selected from the group consisting of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol % and a degree of saponification of at least 40%, carboxylic acid-modified polyolefin and boronic acid-modified polyolefin.
In a preferable embodiment, the compatibilizer (C) is a resin composition comprising 2 to 98 wt % of polyamide and 2 to 98 wt % of carboxylic acid-modified polyolefin.
In a preferable embodiment, the thermoplastic resin (D) is polyethylene having a density of at least 0.93 g/cm3.
In a more preferable embodiment, the whole or a part of the molded component is formed by injection molding.
In a preferable embodiment, the molded component is a multilayered molded component having a multilayered structure and comprising the barrier resin (A) and the thermoplastic resin (B), the barrier resin being at least one selected from the group consisting of polyvinyl alcohol resin, polyamide and aliphatic polyketone.
In a preferable embodiment, the barrier resin (A) is an ethylene-vinyl alcohol copolymer (A1) having an ethylene content of 5 to 60 mol % and a degree of saponification of at least 85%.
In another preferable embodiment, the barrier resin (A) is a resin composition comprising 10 to 80 wt % of ethylene-vinyl alcohol copolymer, 1 to 90 wt % of a compatibilizer (C) and 0 to 89 wt % of a thermoplastic resin (D) having a solubility parameter (calculated from the Fedors"" equation) of not more than 11 other than (A) or (C).
In another preferable embodiment, the compatibilizer (C) is selected from the group consisting of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol % and a degree of saponification of at least 40%, carboxylic acid-modified polyolefin and boronic acid-modified polyolefin.
In a preferable embodiment, the compatibilizer (C) is a resin composition comprising 2 to 98 wt % of polyamide and 2 to 98 wt % of carboxylic acid-modified polyolefin.
In a preferable embodiment, the thermoplastic resin (B) is a polyolefin resin.
In a preferable embodiment, the thermoplastic resin (B) comprises polyethylene having a density of at least 0.93 g/cm3.
In a more preferable embodiment, the thermoplastic resin (B) is selected from the group consisting of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol % and a degree of saponification of at least 40%, carboxylic acid-modified polyolefin and boronic acid-modified polyolefin.
In a more preferable embodiment, the thermoplastic resin (B) is a resin composition comprising 1 to 99 wt % of a compatibilizer (C) selected from the group consisting of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol % and a degree of saponification of at least 40%, carboxylic acid-modified polyolefin and boronic acid-modified polyolefin, and 1 to 99 wt % of a thermoplastic resin (D) having a solubility parameter (calculated from the Fedors"" equation) of not more than 11 other than (C).
In a more preferable embodiment, at least one layer of the barrier resin (A) layer or the thermoplastic resin (B) layer contains 1 to 50 wt % of inorganic filter.
In a preferable embodiment, the molded component is molded with a multilayer injection molding machine, a two-color molding machine, or a co-injection molding machine.
In a more preferable embodiment, the molded component is mounted on a fuel container body via the thermoplastic resin (B) layer.
In a preferable embodiment, the molded component is a connector for a fuel container, a cap for a fuel container or a valve for a fuel container.
In a preferable embodiment, the molded component is mounted on a fuel container body by thermal fusion.
Furthermore, the present invention relates to a fuel container where a component formed of a thermosetting resin (E) is mounted on a fuel container including a fuel container body and a molded component mounted on the fuel container body, the molded component obtained by mixing or laminating the barrier resin (A) and the thermoplastic resin (B), and the component formed of the thermoplastic resin (E) is mounted on the fuel container via the molded component.
In a preferable embodiment, the thermosetting resin (E) is polymethylene oxide.
The above-described present invention provides a molded component for a fuel container providing excellent performance in gasoline barrier properties, thermal fusion properties and mechanical strength, and thus solves the above problems.